AWS S3 bucket NodeJS

hi

I have a SAAS (MERN Stack) application that allows users to upload their documents to AWS S3. I have made the bucket to be private so that the files are not publicly accessible. In this SAAS application, I have about 100 users and they are required to log in to upload and view their documents.

I have heard about using signed URL, using VPC endpoints or IP addresses, or using CloudFront. The question is how do I allow the users to view or upload their documents only after they are logged in, and which methods to use? Many thanks in advance.